ASTUtils

ASTUtils provides some utility over parser gem AST, which aims to help analyzing Ruby programs.

Add this line to your application's Gemfile:

gem 'ast_utils'

And then execute:

$ bundle

Or install it yourself as:

$ gem install ast_utils

ASTUTils::Labeling implements local variables labeling.

In Ruby, local variable scope can be nested, and identification on local variables is not trivial. This utility give labels to identify local variables.

require "parser/current"
require "ast_utils"

node = Parser::CurrentRuby.parse(source)
labeled = ASTUtils::Labeling.translate(node: node)

AST has children but no pointer to its parent.

require "parser/current"
require "ast_utils"

node = Parser::CurrentRuby.parse(source)
navigation = ASTUtils::Navigation.from(node: node)

parent = navigation.parent(child_node)

Scope is about scope in Ruby.

It associates outer scope and its inner scope.

require "parser/current"
require "ast_utils"

node = Parser::CurrentRuby.parse(source)
labeled = ASTUtils::Labeling.translate(node: node)
scope = ASTUtils::Scope.from(node: labeled)

scope.root
scope.children(root)
scope.subs(root)

children includes def and iterator block, but subs only includes blocks.

It also defines assignments and references to refere assignments and references for local variables in the scope.

assignments returns pair of:

• Node which implements assignment
• Labeled local variable name which is assigned

Bug reports and pull requests are welcome on GitHub at https://github.com/soutaro/ast_utils.